MIGRATION OF MITOCHONDRIA TO VIRAL ASSEMBLY SITES IN AFRICAN SWINE FEVER VIRUS-INFECTED CELLS

An examination by electron microscopy of the viral assembly sites in V ero cells infected with African swine fever virus showed the presence of large clusters of mitochondria located in their proximity. These cl usters surround viral factories that contain assembling particles but not factories where only precursor membranes are seen. Immunofluoresce nce microscopy revealed that these accumulations of mitochondria are o riginated by a massive migration of the organelle to the virus assembl y sites. Virus infection also promoted the induction of the mitochondr ial stress-responsive proteins p74 and cpn 60 together with a dramatic shift in the ultrastructural morphology of the mitochondria toward th at characteristic of actively respiring organelles. The clustering of mitochondria around the viral factory was blocked in the presence of t he microtubule-disassembling drug nocodazole, indicating that these fi laments are implicated in the transport of the mitochondria to the vir us assembly sites. The results presented are consistent with a role fo r the mitochondria in supplying the energy that the virus morphogeneti c processes may require and make of the African swine fever virus-infe cted cell a paradigm to investigate the mechanisms involved in the sor ting of mitochondria within the cell.